The primary objective of this proposal continues to be the study of aggression-altering drugs on central receptor mechanisms. Special attention will be directed to alterations in receptor kinetics and number, cyclic nucleotide levels and adenylate cyclase activity. In addition to the direct affect of aggression-altering drugs on these neurochemical parameters, we are also examining the interactional effects of drug treatment and aggressive behavior on these same parameters. Thus, the project is continuing the measurement of cyclic nucleotides in braines from animals treated with drugs which facilitate aggression (e.g., 6-hydroxydopamine, monoamine oxidase inhibitors, dibenzazepines, and rubidium) and drugs which have been reported to decrease aggression (beta blockers, neuroleptics and lithium). This project is also concenred with beta adrenergic, dopaminergic, and benzodiazepine binding in these treatment situations. We anticipate carrying out these evaluations in several models of aggression (shock-elicited aggression in rats, isolation-induced fighting in mice, and mouse-killing and intruder-evoked aggression in rats).